Presently, many modern applications require electronic equipment. Therefore, consumers are increasingly demanding more processing power, lower electrical power usage and cheaper devices. As the electronic industry strives to meet these demands and more complicated and denser configurations, miniaturization will result in an extension of the number of chips per wafer and the number of transistors per chip, as well as a reduction in power usage. Plasma-related technology has been gaining popularity since the electronic components are being designed to be lighter, smaller, more multifunctional, more powerful, more reliable and less expensive. The plasma-related technology allows to overcome the traditional limitations of miniaturization, and is widely applied in order to meet continuous demands toward the miniaturization and higher functions of the electronic components.
During the plasma forming process, plasma is formed above a masked surface of a wafer substrate by adding large amounts of energy to a gas. Non-uniform plasma density across the surface of the substrate usually occurs. Typically, the plasma density in a region near the edge of the wafer substrate is less than that at the center. Since the plasma density above the substrate is poorly controlled, improvements for a plasma-related technology continue to be sought.